This invention is in the field of security and access control, and the invention particularly concerns access to coin box locks and other situations wherein a single mechanical key fits a number of locks and wherein there is a need to control the instances of opening each lock and to maintain record thereof.
In the past, a number of electronic security features have been added to mechanical locks which use mechanical types of cylinders. In addition, locking elements controlled by electronic-means have been disclosed in combination with non-mechanical types of tumblers, such as in Clarkson et al. U.S. Pat. No. 4,712,398. Some of the existing electronic systems have employed keypads, some have employed cards, some have had purely electronic, magnetic or optical access control devices, and some have employed mechanical keys equipped with electronic circuitry.
With respect to the present invention, distinction is made among purely electronic, magnetic or optical keys; mechanical keys equipped with electronic, magnetic or optical features; and mechanical keys which operate solely by mechanical bittings, whether those bittings be pin tumbler, dimples or other mechanical patterns.
A key comprised of purely electronic circuitry, magnetic or optical data storage for determining and granting access is an electronic key. In the use of such a key, the circuitry or recorded data is transferred to a reader associated with a lock, and the reader recognizes a pattern or code held by the key. The key does not carry any mechanical cut or bitting configuration needed for granting access. Keys Of this type can be found in U.S. Pat. Nos. 3,797,936 (Dimitriadis), 4,209,782 (Donath et al.), 4,257,030 (Bruhin et al.), 4,620,088 (Flies), 4,659,915 (Flies) and 4,789,859 (Clarkson et al.).
Keys referred to as mechanical keys are those which activate a mechanical device, with a pattern of mechanical bittings, by direct contact with the interpreting device, i.e. the tumblers or other pattern-holding apparatus contained in the lock. In a typical pin tumbler lock, access is granted based on the depth and configuration of key cuts meeting the tumblers. In most cases, once proper alignment is established in the tumblers, the keyholder is able to turn the key to lock and unlock the locking device. However, in some cases of mechanical keys, a push or pull action may be necessary for locking and unlocking of the device. The tumblers mentioned above can be pin tumblers, lever tumblers, disk tumblers, rotary disk tumblers, slider tumblers, or combinations of several of these incorporated within the same lock. Examples of purely mechanical keys are found in U.S. Pat. Nos. 480,299 (Voight), 550,111 (Sargent), 564,029 (Sargent), 3,208,248 (Tornoe), 4,723,427 (Oliver), 4,732,022 (Oliver) and 4,823,575 (Florian et al.).
Examples of mechanical keys equipped with electronic circuitry, magnetic or optical data storage or optical recognizable features can be found in U.S. Pat. Nos. 3,733,862 (Killmeyer), 4,144,523 (Kaplit), 4,326,124 (Faude), 4,562,712 (Wolter), 4,663,952 (Gelhard), 4,686,358 (Seckinger et al.), 5,245,329 (Gokcebay) and 5,140,317 (Hyatt, Jr. et al.). Such keys carry the secondary element, whether it comprises electronic circuitry or some other type of coded data or recognizable pattern, in addition to the key's mechanically operating pattern or bitting. In some instances both mechanical and non-mechanical features of a key are used simultaneously.
Patent No. 5,140,317, referenced above, discloses a combined mechanical lock/key combination Which further includes an electronic feature for permitting opening of each lock in a system of similarly-keyed locks, only when authorized, and with a recording of each lock opening made. The system disclosed in the patent includes a mechanical key with a key cut configuration, and with means for making electrical contact with electronics inside the lock. A separate box is connected by electric wiring to the key, the box including a keypad, a microprocessor, a battery for powering the system and a memory with stored data. The lock includes a retractable blocking means which blocks opening of the lock's bolt, separately from the mechanical bitting, except when prescribed conditions are met. When a solenoid in the lock is activated the blocking means is retracted. The lock also includes its own microprocessor, which controls switching of power to the solenoid, and with a memory within the lock storing data. The microprocessor within the lock compares coded data read from the key with coded data in the memory within the lock, and thus controls powering of the solenoid to situations in which a comparison, made within the lock's microprocessor, determines that coded data read from the key matches coded data in the lock's memory. Also, the lock's microprocessor further calculates a new code for the lock, after each opening of the lock.
The above patent is applicable to coin locks and other situations wherein a mechanical key has bitting matched to a large number of similar locks, but where control of the opening of each lock is desired, and where a record is needed of each lock's opening. The system has been applied to pay telephone coin boxes. However, besides requiring the inclusion of a microprocessor and associated memory within the lock itself, the system of the patent requires additional hardware within the lock casing or the coin box for blocking the opening of the lock except when the microprocessor determines it is proper. The disclosed system thus is applicable only to locks wherein considerable space is available for these added elements, and would be difficult or impossible to implement in situations with little space available. In addition, considerable modification in retrofitting of existing locks is required, increasing cost of implementing the system, in addition to high cost of manufacture and materials.
It is an object of the invention described below to provide a system which is very easily retrofitted into lock systems having a single key operating a number of locks, and which avoids the need for electronics, solenoids or other hardware which would take up space within the coin box or the lock casing adjacent to the lock.